Using acetylcholinesterase purified from electric eel, we will determine the size and shape of native and lytic forms. The subunit composition will be investigated. The N terminal amino acids will be determined and other similar measurements will be made in order to ascertain how many subunits there are and how many are identical. The number and disposition of disulfide bridges, whether intermolecular or intrachain, will be investigated. We plan to separate the tail from the native form and determine its amino acid composition, size, shape and other properties. BIBLIOGRAPHIC REFERENCES: Voss, Houston F., Ashani, Yacov and Wilson, I.B., "A covalent affinity technique for the purification of all forms of acetylcholinesterase", in ed. W. Jackoby and M. Wilchek, "Methods in Enzymology", Vol. XXXIV, "Affinity Techniques, Enzyme Purification: Part B", Academic Press, N.Y., pp. 581-91, 1974. Maglothin, James A., Wins, Pierre and Wilson, I.B., "Reactivation and aging of diphenyl phosphoryl acetylcholinesterase", Biochim. Biophys. Acta 403, 370-87, 1975.